Dyestuffs and dyestuff intermediates



Patented Feb. 5, 1946 UNITED STATES PATENT oer-"ice DYESTUFFS AND DYESTUFF INTERMEDIATES John David Kendall and Douglas James Fry, Ilford, England, assignors to Ilford Limited, Ilford, England, a British company No Drawing. Application August 21, 1941, Serial No. 407,841. In Great Britain October 16,

.6 Claims.

This invention relates to the manufacture of dyestufi intermediates and to the manufacture therefrom of dyestuffs capable of sensitising gelatino-silver halide photographic emulsions.

According to this invention, dyestufl intermediates are produced by reacting a pyrazole-fi-one in which the methylene group in the 4-position is unsubstituted, with an ortho ester of a monocarboxylic acid of the formula: R1-C(ORz)-a where R1 and R2 are alkyl, aryl or aralkyl groups. The course of the reaction may be indicated as follows:

23,011 (I) where the groups R): and Ri are alkyl, aryl, aralkyl or heterocyclic groups. A

As examples of pyrazole--ones which may be employed there may be mentioned l-methyl-S-pyrazolone, 1 3-dimethyl-5-pyrazolone,

, l-phenyl-S-pyrazolone, 3-phenyl-5-pyrazolone,

1 3-diphenyl-5 -pyrazolone, 1-phenyl-3-methyl- 5-pyrazolone, 1-phenyl-3-furyl-5-pyrazolone compounds.

The ortho ester employed may be, for example, an ester of orthoacetic acid, orthopropionic acid or orthobenzoic acid. Preferably ethyl ortho esters are employed but other alkyl ortho esters,

and analogous or aryl or aralkyl ortho esters may be employed,

if desired.

According to a further feature of the invencyclic nitrogen base obtainable by elimination of a hydrogen atom and the acid residue from such quaternary salt.

The course of this reaction may be illustrated as follows:

\ RICH HY R4 (11) (In the foregoing formulae D is the residue of a heterocyclic nucleus, R5 is a hydrogen atom or an alkyl, aryl or aralkyl group and Re is an alkyl, or aralkyl group) Where the corresponding heterocyclic nitrogen base is employed the reaction proceeds similarly but the groupings H and Y are not present and therefore the acid HY is not eliminated.

Where the heterocyclic compound contains a reactive amino group the two hydrogen atoms of such amino group are eliminated as RzOH and HY, leaving a nitrogen atom instead 0! the group of Formula II.

Any of the alkyl and aralkyl quaternary salts of heterocyclic nitrogen compounds commonly employed in the manufacture of cyanine dyestuffs may be employed in'the present invention. Examples are the substituted and unsubstituted thiazoles thiazolines, oxazoles, oxazolines, selenazoles, selenazolines, pyridine, quinoline, indolenine, diazines (e. g. pyrimidine) thio-diazoles and quinazoline and the corresponding substituted or unsubstituted polycyclic compounds such as benzthiazoles, naphthathiazoles and anthrathiazoles and also the diazines described in British tion dyestuffs are produced by condensing a compound of the general Formula I with an alkyl or aralkyl quaternary salt of A a heterocyclic nitrogen compound containing an external reactive methyl, mono-substituted methyl or amino group in the uor 'y-position to the heterocyclic nitrogen atom or with a. corresponding heterospecification No. 425,609. I

The quaternary salt employed may be, for example, an alkyl or aralkyl chloride, bromide, iodide, sulphate or perchlorate.- Preferably, however, thequaternary saltemployed is an alkylor aralkyl-'p-toluene sulphonate, e.'g. methyl or ethyl-p-toluene sulphonate,

. tion:

tained as colourless needles melting at 129 C.

As indicated above, the groups R1, R2, R3, R4, R5 and R6 may be alkyl or aralkyl groups; examples are methyl, ethyl, propyl, butyl and higher alkyl groups, benzyl and naphthyl-methyl groups. Thegroups R1, R2, R3, R4 and R5 may also be and groups and examples are vphenyl and'naphthyl groups. Such aryl groups may themselves be substituted, e. g. by alkyl, amino, hydroxy,

alkoxy and oxyalkyl groups and by halogen,

atoms. Either or both of the groups RaandRr may, if desired, be heterocyclic groups, eigifuryl groups. The group R5 may be a hydrogen atom.

. The formation of dyestuffs accordingv to the invention is preferably effected: in thehpresenee" of an acid binding agent such as pyridine orother mild base, it not being. necessary to employ a strong base in order to effect the reaction, The following examples illustrate the inven- Axnixture of 101 gms.. of ethyl orthopropionateand '8-.-.6 g ms. of,- 1 phenyl-3 methyl-5 pyrazolone.I

was boiled for fifteen minutes. The mixture was then cooled whereupon the liquid solidified. The

solid was then recrystallised from ethyl alcohol, I

and washed with ethyl alcohol. The, productwas thus obtained as an almost colourless solid melting'at 120C. 7 1

p I 7 ExAuPLs'III Breparaticm' of- 1 -pheayZ-3-methyl-4- (phenyl i ethoary-methylene)-5-pyra2olone 'ona-o'- -o=o-o 02H.

V g'hooau s4 ('JsHd. i

3 A-mixture of 8.6gms. of1-phenyl- 3-methyl-5 pyrazolone and 11.2 gms. of ethylortho-benzoate' was boiled for fifteen minutes and 'then'dissolved j methyl-alcohol. The mixture wasthen cooled and asmal-l quantity of'water was added; The product'ithen separatedias ayellowsolid which a'fterwashinglwith ethyl a-lcohol'fhadi'axmelting: 1 point of 130C. V 1 j EXAMPLE IV Preparation of a-(2-methyldihydrobenzthiazolylid'ene) -1.4'-isobutylidene-1phenyZ-3-methil -'5' -pyraz0lone A mixture of 0.93 gms. of methyl-p-toluene sulphonate and'0.75:gms. of l-methyl-benzthiazole was-fused'for three hours at -130 C. There was then'added 13 gms. of 1-phenyl-3-methyl- 4+ (ethyl-ethoxy-methylene) -5-pyrazolone and 20 cos; of pyridine. The whole mixture was refluxed for half-an-hour' and cooled whereupon the dyestufi separated as shining red needles with a blue reflex, having a melting'point 01256 C. 7

EXAMPLE V- 7 Preparation of 2-methylctihyarobenztfiiasolyli N" 7 ('10. on... r

| (IJHa CaHs A mixture of 1.49 gms. of l-methylbenzthiazole and 1.86 gms. of. methyl-p-toluene sulphonate was fused for three hours at- 13ll- C. There was then added 2.34'gm's. of l-phenyl-S-methyll- (ethoxy-methyl-methylene) -5-pyrazolone and 20 cos. of pyridine, and themixture refluxed for 1 hours. The mixture was: then cooled and the precipitated dyestufi separated by filtration. It had a melting point of-248" C.

EXAMPLE VI Preparation of 2 rriethyldihydrobenzoxazolyli dene-I .4'-z'sopropyZidene-1 "-phenyl-3"-methyl 5'-pyrazolone q A: mixture of 133: gms. of l methylbenzoxazole and 1.86 gms. of methyl-p-toluene sulphonate wasxfu'sedxfor two. hours at l30-14O CI: There was-then 'added'i2'.3l4 gms. Of"IiIIhBnYI 3 IHethYIF 4- ethoxy-methyl-methylene) -5-pyrazolone'z and 20 cos. of'pyridine andl-the.mixturerwas-refiuxedt for one hour. The mixture was .themdiluted with water and cooled and theprecipitated. dyestuff was. separated. by filtration. Ithadiai melt-' inge-range of ?j0T0 C. withidecomposition.

EXA BLEVIL 1 Preparation of -(2 -m'ethyi dihydrobenzoxaaolalibzAmrLn vm Preparation of a-(Z-methyZ dihydrobenzthi azoZylidene-I) -4'-ethylidene p phenyl-p-(rphenyZ-W-methyl-S'-pyrazolone) A mixture of 0.75 gms. of l-methylbenzthiazole and 0.93 gms. of methyl -'p-toluene sulphonate was fused for three hours at 130-140" C. There was then added 1.54 gms. of l-phenyl-S-methyl- 4-(phenyl-ethoxy-methylene) -5-pyrazolone and 20 cos. of pyridine and the mixture was boiled for half-an-hour. The mixture, was then diluted with water whereupon the crude dyestuff se arated. This was recrystalised from hot' ethyl alcohol and thusobtained as light brown needles, melting at 238 C.

EXAMPLE IX Preparation of N-(z-meth'yl dihydrobenzthiazolyl-I) -a-(1'-phenyl -3'- methyl 5'-pyrazolone-4') -ethylamine g AH.

I EXAMPLE X Preparation of 1-phenyZ-3-furyZ-4-(methyl-ethoxy-methylene) -5-pyrazolone FLU-:0 can 0 it o=o om 4.5 gmsf of phenyl-3-furyl-5-pyrazolone were boiled with gms. of ethyl ortho-acetate for iiiteen minutes; The resulting solutioniwasrcooled whereupon the desired dyes'tuflf intermediate separated. This was removed by filtration and washed with ethyl alcohol. The product had a melting point of -91 C.

EXAMPLE XI Preparation of 2-ethyl-dihydrobenzthiazolyli-' H dene -1.4'-isopropylidene -1'- phenyl -3'-furyliS' -pyrazoZOne' I Y it was obtained asredvcrystals melting at 250C. v

. Acorresponding dyestufi? was obtained by a similar method from the same intermediate using 1 gm. of quinaldine ethiodide instead of the 1- methyl benzthiazole ethiodide. It had a melting point above C. 7

As already indicated, the dyestuffs produced according to this invention are valuable sensitising dyestuffs for gelatino-silver halide photographic emulsions, e. g. silver chloride, bromide, chlorobro'mide and iodobromide emulsions. Those dyestuffs in which the group R5 in Formula II is an alkyl or aralkyl group may also be used as intermediates for the production of further dyestuffs as described in our copending application Serial No. 407,838 filed on even date therewith.

What we claim is:

1. Process for the manufacture of dyestufl intermediates which comprises reacting one mol of a compound of the general formula:

where R1 and R2 are selected from the groiip consisting of alkyl, aryl and aralkyl groups, with one mol of a compound of the general formula:

wherein the Rs have the above significance.

ILR 4 this;

, v'rhere Hi and R2 are'selected ffoin the consisting of alkyl, aryl and aralkyl'groupsandRa and R4 are selected from the groupv consisting of alkyl, aryl and aralkyl groups.

3. A process for themanufacture 'of dyestufi intermediates which comprises reaetingyone mol of an orthosester selected from the group consisting of alkyl esters of ortho acetic acid and of higher homologues of ortho acetic acid with one mol of a compound of the general formula:

"R; 9 wherein Hi. and R4 aresele'ct'ed'fromthe group consisting ofalk'yl, aryiand'araikylgroups in the 'absence of a; condensing agentiby heating said compounds together so as to formtwo'jmols of amonoliydric alcohol'and a; compoundbi-fthe formula: V

R o -c=c Eu N- c =os aikyl v r wherein the Re have the aboveisignificance.

ammo:

rlzl-rnyfistufi" intermediates: whichin-azrepcom ieermdye'stufiwintermediate orrtheziormular 'poundszofz:thegeneraliformulaz Y K i I 7 v 379R) 7 CHr-C 0-0 I V am; i o in theiormroffcolorless needies-noe1tsat 12s c. a r a V 5; A dyestuif intermediate of the formula I ohm,

cHhe -c =e 4- o o;HE-'

which in the form of la substantiaily colorless solid melts-at C;

6. A dyestufi intermediate of the formula 

